Virtuelle (Nano) Welten PDB Molecule of the Month 83: Fibrin

Forming the Fibril

Once fibrin is activated, it assembles to form tough fibrils. The chains at the center reach over and bind into pockets on the large globular heads of neighboring fibrin molecules. Also, fibrin associates head-to-head, as shown in the upper structure from PDB entry 1fzc. This head-to-head interaction is made stronger in a clot by crosslinking, making the interaction permanent. Finally, the longer chains colored orange here can extend over to neighboring fibrils to form even larger structures, binding in a small pocket colored green here.